In Noah Baumbach's new film Greenberg, Ben Stiller plays a curmudgeon who's more likely to push people away than attract them. And that's precisely why LCD Soundsystem's James Murphy, who wrote the soundtrack, likes the character so much. "I'm Greenberg-esque," Murphy says proudly.

In fact, Murphy's music was a chief inspiration for the movie: Baumbach was obsessed with LCD Soundsystem's sarcastic ballad "New York, I Love You But You're Bringing Me Down" while writing the script of a sad-sack Manhattanite living in L.A. So when it came time to approach someone to craft the soundtrack, Baumbach immediately thought of Murphy. "It's not like it was a stretch, like what would I do if I were a serial killer?" says Murphy about relating to the movie's plot. "It was more like, what would I do if I were a 40-year-old grumpy dude out of place in Los Angeles? It was real method for me, but I can get into that."

Murphy has never scored a film before but he agreed to the project so he could take a break from working on LCD's next album, due out this May. "When given the opportunity to fail myself or fail someone else, I choose to fail myself," he jokes. When it came time to write, Murphy deliberately chose to move away from typical soundtrack cliches — "[Soundtracks] are just these tones… and sounds all over the place," he says — and would check in with Baumbach regularly while the director was still editing the movie. "We'd sit and talk, we'd have tea, I'd pet his dog, and we'd look at [scenes]," Murphy says. "It literally could have been two roommates who were making a movie for $15,000."

The resulting Greenberg soundtrack sounds nothing like LCD Soundsystem: Seventies-style California pop that calls to mind Harry Nilsson and Brian Wilson. "Please Don't Follow Me," with its pounding piano riff and bright brass tones, is one of the catchier numbers. Still, LCD fans will find that tracks like the psychedelic freakout "Oh No (Christmas Blues)" hew closer to Murphy's trademark dance-punk style. "This is how I think scores should sound," Murphy says. "I'd rather just make stereo music to put into a song, not give somebody all the parts to be spread around the sound spectrum."

For all his troubles, Murphy got to make a cameo in the movie in a blink-and-you'll-miss-him moment. "I'm one of the people in the party scene," he says. "I didn't have a bunch of lines. I just walk from here to there. And I look like a Sasquatch."